土地的价值是无法确定的。It is impossible to be sure about the value of land.她的眼神里有种难以确定的东西。There was something indefinable in her eyes.这座建筑物的确切年代是可以确定的.It is possible to assign an exact date to this building....
She jumped the fourth grade in primary school.她跳过了小学四年级.Children enter primary school at the age of 7.孩子们7岁进小学.I started primary school when I was 5 years old.我五岁时开始读小学....